As quantitative data from a wide variety of techniques and levels of investigation become available for a particular nervous system function, it is both possible and advisable to attempt to assimilate such information into a comprehensive model of the underlying mechanisms and their interactions. This project consists of the development of such models and the necessary analytical and mathematical techniques for their implementation and testing in several areas of intensive experimental investigation by LNLC members and the scientific community at large. The kinematic model of the cat hindlimb initiated last year in collaboration with the University of Maryland has begun to yield experimentally verifiable time courses of muscle lengths and joint angles, and also, recently, of joint torques. Our new system of computer programs for data analysis and display within the UNIX operating system averages EMG signals recorded during a number of steps, compensating for natural variability in the steps. The system superimposes these EMG signals on graphs of lengths of the same muscles from the kinematic model so that muscles active during shortening versus lengthening can be detected and compared.